Can the IRS be so adamant about your tax debt that they levy your social security benefits? The answer is yes. The IRS can levy up to 15% of your social security retirement income. In fact, if you do not reply, they often levy this source of income until you resolve your tax situation. Also, they will continuously levy this source until the tax debt is resolved by payment in full or another tax resolution option (abatement of tax, CNC, OIC, or Installment Agreement, etc.)
Interesting to note, the IRS does not levy SSI payments for hardships. Technically, they are leviable, but the current IRS policy is not to do so.
If your SSA benefits are levied, you may want to seek professional help.